U.S. patent number 4,680,933 [Application Number 06/785,283] was granted by the patent office on 1987-07-21 for control device for an internal combustion engine with an exhaust gas turbocharger.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Hanns-Gunther Bozung, Joachim Nachtigal.
United States Patent |
4,680,933 |
Bozung , et al. |
July 21, 1987 |
Control device for an internal combustion engine with an exhaust
gas turbocharger
Abstract
An exhaust gas turbocharger consists of an exhaust gas turbine
and a compressor mounted on a common shaft which can be driven by
an electric motor controlled via a controller. The controller,
which is designed as a computer, receives as control data the
control input supplied to the controller of the internal combustion
engine as the set value and actual performance values. The
controller computes and supplies, from the received control data
and from stored values, control signals by which, in the
motor-operating mode of the electric motor, the internal combustion
engine accelerates as quickly as possible at combustion air ratios
optimal for low-smoke combustion and by which, in the
generator-operating mode of the electric motor, a maximum of excess
exhaust gas energy can be fed to an electric accumulator network as
electrical energy via a static converter. The switch from motor to
generator operation and vice versa is controlled as a function of a
presettable charging air pressure value, or a charging air pressure
valve computed by the controller, or of the output of the internal
combustion engine.
Inventors: |
Bozung; Hanns-Gunther (Neusass,
DE), Nachtigal; Joachim (Hetzles, DE) |
Assignee: |
Siemens Aktiengesellschaft
(Munich, DE)
|
Family
ID: |
6247999 |
Appl.
No.: |
06/785,283 |
Filed: |
October 7, 1985 |
Foreign Application Priority Data
|
|
|
|
|
Oct 16, 1984 [DE] |
|
|
3437872 |
|
Current U.S.
Class: |
60/608;
290/52 |
Current CPC
Class: |
F02D
41/0007 (20130101); F02B 37/10 (20130101); F02B
37/14 (20130101); F02B 39/10 (20130101); F02B
37/005 (20130101); Y02T 10/12 (20130101) |
Current International
Class: |
F02B
39/10 (20060101); F02B 39/02 (20060101); F02D
41/00 (20060101); F02B 37/12 (20060101); F02B
37/14 (20060101); F02B 033/44 () |
Field of
Search: |
;60/607,608 ;290/52 |
Foreign Patent Documents
|
|
|
|
|
|
|
0079100 |
|
May 1983 |
|
EP |
|
2206450 |
|
Aug 1973 |
|
DE |
|
101540 |
|
Jun 1984 |
|
JP |
|
681204 |
|
Aug 1979 |
|
SU |
|
Primary Examiner: Husar; Stephen F.
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. A control device for an internal combustion engine with an
exhaust gas turbocharger having an exhaust gas turbine and a
compressor both mounted on a common shaft, which can be driven by
an electric motor, said turbine transferring the electric motor
from motor operation to generator operation in the event of excess
power in the exhaust gases so as to furnish electrical energy from
the electric motor to an electric accumulator, or an independent
load, via a static converter, comprising:
(a) a plurality of sensors that detect the instantaneous values of
(a) the actual rotary speed of the turbocharger, (b) the actual
voltage of the electric accumulator, (c) the actual frequency of
the electric accumulator, and (d) the actual charging air pressure
of the compressor; and
(b) a computer controller which (a) receives as control data the
detected values from the plurality of sensors, a control input
received by a controller of the internal combustion engine, and
engine output data, and (b) computes and supplies from the control
data received and from stored values, in particular, from a
charging air pressure characteristic or from an input
characteristic to the electric motor as a function of the output of
the internal combustion engine, control signals for the static
converter by which, in the motor-operating mode of the electric
motor, the internal combustion engine accelerates as quickly as
possible at combustion air ratios optimal for low-smoke combustion,
and by which, in the generator-operating mode of the electric
motor, a maximum yield of electrical energy from the excess exhaust
gas energy can be fed to the electric accumulator or to the
independent load, the transferring of the electric motor from motor
operation to genertor operation and vice versa being controlled as
a function of a charging air pressure value preset in the computer
controller and the computer controller being usable in conjunction
with an exhasut gas turbocharger which, due to optimized exhaust
gas turbine and compressor blade design, is of such high efficiency
that it is not necessary to utilize the entire amount of exhaust
gas available for generating the amount of charging air required in
the upper load range of the internal combustion engine, with the
charging air pressure required for an optimum combustion air ratio,
and that the exhaust gas energy attainable without increased fuel
intake can be utilized for conversion into electrical energy.
2. The control device as set forth in claim 1, wherein: the
electric accumulator is an electrical network comprising a
plurality of motor-generator sets and laods.
3. The control device as set forth in claim 1, wherein: the
electric motor comprises an asynchronous machine.
4. The control device as set forth in claim 1, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
5. The control device as set forth in claim 2, wherein: the
electric motor comprises an asynchronous machine.
6. The control device as set forth in claim 2, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
7. A control device for an internal combustion engine with an
exhaust gas turbocharger having an exhaust gas turbine and a
compressor both mounted on a common shaft, which can be driven by
an electric motor, said turbine transferring the electric motor
from motor operation to generator operation in the event of excess
power in the exhaust gases so as to furnish electrical energy from
the electric motor to an electric accumulator, or an independent
load, via a static converter, comprising:
(a) a plurality of sensors that detect the instantaneous values of
(a) the actual rotary speed of the turbocharger, (b) the actual
voltage of the electric accumulator, (c) the actual frequency of
the electric accumulator and (d) the actual charging air pressure
of the compressor; and
(b) a computer controller which (a) receives as control data the
detected values from the plurality of sensors, a control input
received by a controller of the internal combustion engine, and
engine output data and (b) computes and supplies from the control
data received and from stored values, in particular, from a
charging air pressure characteristics or from an input
characteristic to the electric motor as a function of the output of
the internal combustion engine, control signals for the static
converter by which, in the motor-operating mode of the electric
motor, the internal combustion engine accelerates as quickly as
possible at combustion air ratios optimal for low-smoke combustion,
and by which, in the generator-operating mode of the electric
motor, a maximum yield of electrical energy from the excess exhaust
gas energy can be fed to the electric accumulator or to the
independent load, the transferring of the electric motor from motor
to operation generator operation and vice versa being controlled as
a function of a charging air pressure value computed by the
computer controller and the computer controller being usable in
conjunction with an exhaust gas turbocharger which, due to
optimized exhaust gas turbine and compressor blade design, is of
such high efficiency that it is not necessary to utilize the entire
amount of exhaust gas available for generating the amount of
charging air required in the upper load range of the internal
combustion engine, with the charging air pressure required for an
optimum combustion air ratio, and that the excess exhaust gas
energy attainable without increased fuel intake can be utilized for
conversion into electrical energy.
8. The control device as set forth in claim 7, wherein: the
electric accumulator is an electrical network comprising a
plurality of motor-generator sets and loads.
9. The control device as set forth in claim 7, wherein: the
electric motor comprises an asynchronous machine.
10. The control device as set forth in claim 7, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
11. The control device as set forth in claim 8, wherein: the
electric motor comprises an asynchronous machine.
12. The control device as set forth in claim 8, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
13. A control device for an internal combustion engine with an
exhaust gas turbocharger having an exhaust gas turbine and a
compressor both mounted on a common shaft, which can be driven by
an electric motor, said turbine transferring the electric motor
from motor operation to generator operation in the event of excess
power in the exhaust gases so as to furnish electrical energy from
the electric motor to an electric accumulator, or an independent
load, via a static converter, comprising:
(a) a plurality of sensors that detect the instantaneous values of
(a) the actual rotary speed of the turobcharger, (b) the actual
voltage of the electric accumulator, (c) the actual frequency of
the electric accumulator, and (d) the actual charging air pressure
of the compressor; and
(b) a computer controller which (a) receives as control data the
detected values from the plurality of sensors, a control input
received by a controller of the internal combustion engine, and
engine output data, and (b) computes and supplies from the control
data received and from stored values, in particular, from a
charging air pressure characteristic or from an input
characteristic to the electric motor as a function of the output of
the internal combustion engine, control signals for the static
converter by which, in the motor-operating mode of the electric
motor, the internal combustion engine accelerates as quickly as
possible at combustion air ratios optimal for low-smoke combustion,
and by which, in the generator-operating mode of the electric
motor, a maximum yield of electrical energy from the excess exhaust
gas energy can be fed to the electric accumulator or to the
independent load, the transferring of the electric motor from motor
operation to generator operation and vice versa being controlled as
a function of the internal combustion engine output and the
computer controller being usable in conjunction with an exhaust gas
turbocharger which, due to optimized exhaust gas turbine and
compressor blade design, is of such high efficiency that it is not
necessary to utilized the entire amount of exhaust gas available
for generating the amount of charging air required in the upper
load range of the internal combustion engine, with the charging air
pressure required for an optimum combustion air ratio, and that the
exhaust gas energy attainable without increased fuel intake can be
utilized for conversion into electrical energy.
14. The control device as set forth in claim 13, wherein: the
electric accumulator is an electrical network comprising a
plurality of motor-generator sets and loads.
15. The control device as set forth in claim 13, wherein: the
electric motor comprises an asynchronous machine.
16. The control device as set forth in claim 13, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
17. The control device as set forth in claim 14, wherein: the
electric motor comprises an asynchronous machine.
18. The control device as set forth in claim 14, wherein: the
electric motor comprises a permanent magnet-excited synchronous
motor.
Description
TECHNICAL FIELD
The invention relates generally to a control device for an internal
combustion engine. In particular, the invention relates to a
control device for an internal combustion engine with an exhaust
gas turbocharger.
BACKGROUND OF THE INVENTION
In many applications, it is now common for an internal combustion
engine to utilize an exhaust gas turbocharger to improve
performance. A turbocharger is a device that uses the exhaust gas
of the internal combustion engine to drive a supercharger attached
to the engine. The turbocharger usually comprises an exhaust gas
turbine and a compressor, both mounted on a common shaft which can
be driven by an electric motor. The turbine transfers or switches
the electric motor from motor operation to generator operation in
the event of excess power in the exhaust gases so to furnish
electrical energy to an electric accumulator via a static
converter. A control device is fed the actual rotary speed of the
turbocharger and the actual voltage of the electric accumulator
from respective sensors and an acceleration signal from a
transmitter. From the signals provided, the control device forms
control signals for the static converter by which the internal
combustion engine is accelerated quickly during the motor-operating
mode of the electric motor and the power furnished by the electric
motor is rectified during the generator-operating mode.
A control device of the type described above is found in the
European Patent Office patent document No. EP-A 0079100. The
reference discloses that the electrical energy furnished in the
generator-operating mode of the electric motor is supplied to a
battery acting as the electric accumulator in order to have the
energy available again for a subsequent turbocharger acceleration
process. Switching the electric motor from motor operation to
generator operation and vice versa is accomplished by means of a
mechanical or electronic switching relay as a function of the
turbocharger speed, the battery voltage and the acceleration
signal. During the generator-operating mode, energy is supplied to
the battery via an uncontrolled rectifier bridge. During the
motor-operating mode, energy from the battery is fed to the stator
winding of the electric motor via an inverter controlled by the
control device. The rectifier bridge and the inverter may be
replaced by a bi-directional static conterter.
Although the aforedescribed control device makes quick acceleration
of the internal combustion engine possible, low-smoke combustion
and low fuel consumption, which are both desirable and
advantageous, are not obtainable for the following reasons. The
amount of fuel supplied to an internal combustion engine is
directly proportional to the signal emitted by an acceleration
transmitter. For smoke-free combustion, i.e. combustion at the
optimum fuel/air ratio, the supplied amount of fuel requires a
closely defined amount of combustion air. The aforesdescribed
control device can produce exhaust gas containing excess energy,
however, only at the expense of excess fuel intake to the internal
combustion engine. This automatically leads to a fuel/air ratio
unfavorable for combustion and, hence, to exhaust gas turbidity.
Neither this excess fuel supply nor the resultant fuel/air ratio
for the generation of otherwise useable excess exhaust gas energy
are desirable. Disadvantageously, the higher amount of fuel also
increases the operating costs. Lastly, the worsened exhaust gas
composition is usually impermissible, especially from the aspect of
the exhaust gas ordinances in force.
Another control device for an internal combustion engine with an
exhaust gas turbocharger is described in the German Pat. DE-A No.
22 06 450. The turbocharger comprises an exhaust gas turbine and a
compressor mounted on a common shaft. The shaft can be driven by an
electric motor controlled so that, in the event of excess power in
the exhaust gases, the electric motor is switched from motor
operation to generator operation and electrical energy is supplied
to a network fed by a supply source. The decisive evaluation and
comparison criterion disclosed therein is that the electric motor
keeps the speed of the disengaged turbocharger constant in the
entire load range of the internal combustion engine by means of an
appropriate control device. Thus, the turbocharger compressor
always furnishes, regardless of the momentary loading of the
internal combustion engine, an output of constant level with the
result that the internal combustion engine is always offered a
constant amount of air of constant charging air pressure.
Consequently, if the internal combustion engine is to be
accelerated from idling, for instance, the excess air prevailing in
the lower and medium partial load range will force an increased
fuel intake to ensure the fuel/air ratio required in the internal
combustion engine.
According to another disclosed criterion of the German patent, the
control device is designed so that, in the event of excess pwoer at
the exhaust gas turbine, the electric motor is switchable to
generator operation and electrical energy can then be supplied to
the network fed by the supply source. However, assuming that the
electric motor in its motor-operating mode drives the turbocharger
at constant speed (i.e., for constant charging air pressure and
constant amount of charging air) over the entire load range of the
internal combustion engine, such a power excess, capable of causing
the electric motor to switch from motor to generator operation, in
the exhaust gases supplied to the exhaust gas turbine for
conversion into electrical energy can be achieved only by an
increased fuel intake.
Therefore, it is an object of the invention to improve a control
device of the kind defined at the outset so that, in operating an
internal combustion engine with less fuel consumption than in
previously known arrangements, better acceleration of the internal
combustion engine in the partial load range, particularly for
starting and in the lower part of the load range, as well as a most
favorable conversion of excess exhaust gas energy into electrical
energy is possible. It is a further object of the invention that
the electrical energy from such a conversion is not to be supplied
to a battery, but to a consumer load to be provided and present in
the surroundings of the internal combustion engine and whose
specific data must also be taken into account in the design of the
control device.
SUMMARY OF THE INVENTION
According to the invention, the foregoing problems are obviated by
a control device, comprising: (a) a plurality of sensors that
detect the instantaneous values of (a) the actual rotary speed of
the turbocharger, (b) the actual voltage of the electrical
accumulator, (c) the actual frequency of the electric accumulator
and (d) the actual charging air pressure of the compressor; and (b)
a computer controller which (a) receives as control data the
detected values from the plurality of sensors, a control input
received by a controller of the internal combustion engine, and
engine output data, and (b) computes and supplies from the received
control data and from stored values, in particular, from a charging
air pressure characteristic or from an input characteristic to the
electric motor as a function of the internal combustion engine
output, control signals for triggering the static converter by
which, in the motor-operating mode of the electric motor, the
internal combustion engine accelerates as quickly as possible at
combustion air ratios optimal for smokeless combustion and by
which, in the generator-operating mode of the electric motor, a
maximum yield of electrical energy from the exhaust gas energy can
be fed to the electric accumulator or to the independent load, the
transferring of the electric motor from motor operation to
generator operation and vice versa being controlled as a function
of a charging air pressure value preset in the computer controller
or of a charging air pressure value computed by the computer
controller or of the internal combustion engine output.
The electrical accumulator used with the control device of the
present invention can be an electrical network, in particular, a
network comprising a plurality of motor-generator sets and
loads.
The control device can be used in conjunction with an exhaust gas
turbocharger which, due to an optimized blade design of the exhaust
gas turbine and the compressor, is of such high efficiency that it
is not necessary to utilize the entire amount of exhaust gas
available for generating the amount of charging air required in the
upper load range of the internal combustion engine, with the
charging air pressure required for an optimum combustion air ratio,
and the excess exhaust gas energy attainable without increased fuel
intake is useable for conversion into electrical energy.
It is possible with such a control device to obtain any desired
internal combustion engine acceleration adapted to the desired
operating mode, always at the optimized combustion air ratio. As a
result of the always optimized combustion air ratio, a noteworthy
reduction in fuel consumption is obtained. In addition, due to
improved utilization of the energy contained in the exhaust gas,
the efficiency of the system is improved considerably in the
generator-operating mode because the most advantageous combustion
air ratio is always present, even in the higher speed range and
load range of the internal combustion engine. The latter is also
assured, in particular, with respect to the control device used in
conjunction with the above-mentioned turbocharger whose efficiency
is so high on account of an optimized blade design of the exhaust
gas turbine and the compressor.
This decisive advance achieved by the control device of the present
invention has thus become possible only through the optimization of
exhaust gas turbochargers. It is of particular advantage, for
example, in the application of the internal combustion engine as
the means to propel ships, because the electrical energy obtainable
from the excess exhaust gas energy through appropriate conversion
alone is already sufficient in many cases to adequately supply the
entire electrical ship network and the loads connected thereto.
This, in turn, makes it possible to design a Diesel-generator set,
which is present on board a ship and independent of the internal
combustion engine system for generating the electrical energy to
cover the basic need of the existing electrical ship network and of
the loads connected thereto, smaller with respect to its power
output.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference is made to
the following description of an exemplary embodiment thereof and to
the accompanying drawing therein:
FIG. 1 is a block diagram of a control device for an internal
combustion engine with a plurality of exhaust gas
turbochargers.
DETAILED DESCRIPTION
In FIG. 1, an internal combustion engine 10, e.g. one designed as a
Diesel engine, has an associated exhaust gas turbocharge 12
comprising an exhaust gas turbine 14 and a compressor 16 mounted on
one common shaft 17. The exhaust gas turbocharger 12 can be driven
by an electric motor 18 connected to the shaft 17 via a coupling
19. The electric motor 18 is also connected to a static converter
20.
The static converter 20 is expediently designed as a pulsed
inverter with an intermediate D.C. link 21. The static converter 20
contains a machine-controlled inverter 22 which is connected to a
network-controlled reversing converter 24 via the intermediate D.C.
link 21. The inverter 22 is triggered by a first control unit 26 in
a converter control 25. Similarly, a second control unit 28 in the
converter control 25 is associated with the network-controlled
reversing converter 24.
The electric motor 18 is connected via the static converter 20 to
an electrical network 30 which is fed by a plurality of
Diesel-generator sets 32, 34. A plurality of loads 36, such as
heaters, air conditioners, transformers, lights and the like are
connected to the network 30.
A controller 40 for the electric motor 18 is designed as a
computer. The controller 40 receives from a first sensor 41,
designed for instance, as a tachometer generator, a value
proportional to the speed of the turbocharger 12 as the actual
value and from a second sensor 43, a value proportional to the
charging air pressure P as the actual value. In addition, the
controller 40 receives from a third sensor 45, and actual value
proportional to the voltage and/or frequency of the network 30.
The internal combustion engine 10 is also equipped with a
controller 50 to regulate the fuel supply through the fuel
injection system 52. The engine output is preset by control input
sent via a set point adjuster 54. The control input supplied to the
engine controller 50 is also fed to the electric motor controller
40. Note that an engine sensor 55 feeds engine data back to the
engine controller 50.
From the set and actual values received and from stored values (in
particular, from a charging air pressure P characteristic or a
power input characteristic of the electric motor 18 as a function
of the output of the internal combustion engine 10), the controller
40 computes and supplies control values for the control units 26,
28 of the static converter 20, by which, the internal combustion
engine 10 accelerates as quickly as possible despite the fact that
the combustion air ratios are optimal for low-smoke combustion. The
control values supplied to the static converter 20 via the control
25 also determine the power output and, hence, the speed of the
electric motor 18. Note that the second control unit 28 also
receives reference values from the network 30 via the third sensor
45.
In the event of excess power in the exhaust gases, the electric
motor 18 is switched from motor to generator operation by
appropriate triggering the static converter 20. In the
generator-operating mode fo the electric motor 18, a maximum of
excess exhaust gas energy can be fed into the network 30 as
electrical energy or supplied to a load 60 independent of the
network 30. Switching the electric motor 18 from motor to generator
operation and vice versa is controlled as a function of a charging
air pressure P value preset in the controller 40 or of a charging
air pressure P value computed by the controller 40 or of the power
output of the internal combustion motor 10. In this process, the
control inputs supplied to the static converter 20 determine the
output of the electric motor 18 operating as a generator.
Special advantages result from using the controller 40 in
conjunction with an exhaust gas turbocharger 12 whose efficiency
due to optimized turbine 14 and compressor 16 blade design is such
that not all of the available exhaust gas energy is used to
generate the amount of charging air and the charging air pressure
required in the upper load range of the internal combustion engine
10 and that the excess exhaust gas energy thus available without
increased fuel intake can be utilized for conversion into
electrical energy. An optimization is achieved, for example, by
using compressor impellers with blades curved backwards and/or
adjustable diffusers.
Depending on the rate output or number of cylinders of the internal
combustion engine 10, several exhaust gas turbochargers may be
used. As shown in FIG. 1, the internal combustion engine 10 has, in
addition to the first turbocharger 12, a plurality of exhaust gas
turbochargers 12a, 12b which are triggered jointly by the electric
motor controller 40 and whose respective electric motors 18a, 18b
are operated via the common static converter 20.
If the plurality of electric motors are designed as asynchronous
motors, they act like ordinary machines connected to a common
network when voltage and frequency are changed. However, the
electric motors may also be synchronous machines, in particular,
permanent magnet-excited synchronous motors.
It is purposeful to equip each electric motor 18, 18a, 18b with a
spray oil cooling system. This makes for a compact design and makes
installation, for example, in the intake muffler of the respective
exhaust gas turbocharger 12, 12a, 12b possible.
It is to be understood that the embodiments described herein are
merely illustrative of the principles of the invention. Various
modifications may be made thereto by persons skilled in the art
without departing from the spirt and scope of the invention.
* * * * *